Spidey Senses

George Uetz, UC professor of biological sciences in the McMicken College of Arts and Sciences, has been studying spiders since his days of graduate school at University of Illinois in the 1970s. Recently, he and colleague David Clark of Alma College were funded with $457,381 from the National Science Foundation for “Collaborative Research: Sensory Ecology of an Animal Communication Network.”

You’ve been studying spiders for more than three decades. What makes them such great ecological test subjects?

Spiders are fascinating animals, and yet we know very little about them compared to other animal groups. They are abundant and common in most ecosystems, and they play important ecological roles, e.g., as predators of insects, and prey for other animals. Most important in the case of my research is that spiders exhibit diverse and complex behaviors that allow us to test a variety of hypotheses about the evolution of behavior in a very different kind of animal model.

Biology Professor George Uetz shares his expertise on spiders with students at UC and Alma College.

In the past, you’ve studied colonial web-building spiders in Mexico, and El Niño effects on spider populations in California. This NSF grant will focus more on communication. From what does this interest stem? What are the goals of this research project?

Actually, this project is a continuation of NSF-sponsored work that has been going on as a separate research track for some time. It originated with a discovery made in my first year at UC—that two wolf spiders diverged and evolved into separate species as a consequence of differences in behaviors used in courtship communication.

Communication is a fundamental aspect of most animals’ lives, but is especially critical for species and mate recognition in predatory and potentially cannibalistic animals like spiders. Male spiders produce complex signals that are conspicuous and attractive to females, but are also exploited by “eavesdroppers”—other competitor males and predators. Spiders are also very small and live in a physical environment that makes communication difficult. As a consequence, evolution of signals is influenced by multiple factors that arise from the environment in which communication takes place, as well as the types of animals involved in communication. In our study, we will examine how the physical environment of forest floor leaf litter (light spectrum, vegetation background) affects detection and discrimination of male signals by female wolf spiders and eavesdroppers (male wolf spiders, predatory toads and jumping spiders).

What sensory characteristics are specific to wolf spiders?

While we think of invertebrates as simple animals, they really aren’t. Evolution has resulted in spiders having very different (and in some ways more sophisticated and/or sensitive) sensory capabilities than vertebrate animals. The wolf spider species we are working with—Schizocosa ocreata—has the capacity to detect, discriminate and evaluate other spiders (species identity, mate quality), prey insects, environmental cues (light level, spectrum, vibration) and predatory threats (birds, toads, other spiders) using multiple senses (vision, vibration senses, olfaction)—and integrate all this information with a “brain” smaller than the head of a pin! This makes them a great model for understanding interactions between the physical and biological environment, the nervous system and behavior.What are the broader implications of your research?

Understanding the relationship between animal signals, the constraints of the physical environment, and the integration of sensory information with behavior concerns fundamental questions in animal behavior, neurobiology and evolution (e.g., how the brain extracts important visual and auditory information from a chaotic sensory environment). Basic research in this area may ultimately provide insights that lead to applications in robotics and technologies associated with signal detection and processing, as well as certain aspects of human health.

You are working with Alma College’s David Clark on this project. Why is it important to build collaborations with smaller liberal arts colleges?

A lot of our graduate students come from small colleges, and so it is a great way to recruit new ones. Dr. Clark is a former UC PhD student, and like a number of our graduates, is now a professor at a small liberal arts college (Alma College). Our collaboration not only allows us to combine different skills in research, but will involve graduate students from UC and undergraduate students from both institutions in a unique research student exchange program, as well as “capstone experience” and “spring term” courses. We hope this will actively engage students in the research process.